U.S. patent application number 13/875677 was filed with the patent office on 2014-11-06 for method and apparatus for device to device relay selection.
This patent application is currently assigned to QUALCOMM Incorporated. The applicant listed for this patent is QUALCOMM INCORPORATED. Invention is credited to Qing He, Junyi Li, Bilal Sadiq, Saurabha R. Tavildar.
Application Number | 20140329535 13/875677 |
Document ID | / |
Family ID | 50972776 |
Filed Date | 2014-11-06 |
United States Patent
Application |
20140329535 |
Kind Code |
A1 |
Sadiq; Bilal ; et
al. |
November 6, 2014 |
METHOD AND APPARATUS FOR DEVICE TO DEVICE RELAY SELECTION
Abstract
A method, an apparatus, and a computer program product for
wireless communication are provided in connection with D2D relay
link selection in a LTE based access network. In one example, a
communications device is equipped to determine that the
communications device (e.g., a UE) is able to establish a relay
link with a candidate UE based on at least one of information
associated with any preexisting access links with the candidate UE,
information associated with any preexisting accessing links within
a threshold vicinity of the UE or the candidate UE, or any other UE
UL interference, determine that the candidate UE is able to support
the relay link based on information associated with preexisting
access links for the candidate UE, and perform a link establishment
process for the relay link with the candidate UE based on the
determinations.
Inventors: |
Sadiq; Bilal; (Somerville,
NJ) ; He; Qing; (Cambridge, MA) ; Tavildar;
Saurabha R.; (Jersey City, NJ) ; Li; Junyi;
(Chester, NJ) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
QUALCOMM INCORPORATED |
San Diego |
CA |
US |
|
|
Assignee: |
QUALCOMM Incorporated
San Diego
CA
|
Family ID: |
50972776 |
Appl. No.: |
13/875677 |
Filed: |
May 2, 2013 |
Current U.S.
Class: |
455/452.2 |
Current CPC
Class: |
H04W 76/14 20180201;
H04W 88/04 20130101 |
Class at
Publication: |
455/452.2 |
International
Class: |
H04W 88/04 20060101
H04W088/04 |
Claims
1. A method of communications, comprising: determining that a user
equipment (UE) is able to establish a relay link with a candidate
UE based on at least one of information associated with any
preexisting access links with the candidate UE, information
associated with any preexisting access links within a threshold
vicinity of the UE or the candidate UE, or any other UE uplink (UL)
interference; determining that the candidate UE is able to support
the relay link based on information associated with preexisting
access links for the candidate UE; and performing a link
establishment process for the relay link with the candidate UE
based on the determinations.
2. The method of claim 1, further comprising: receiving a list of
one or more candidate UEs from an eNodeB.
3. The method of claim 1, further comprising: performing
measurements to detect one or more candidate UEs.
4. The method of claim 1, wherein the relay link comprise at least
one of an UL relay link, a downlink (DL) relay link, or UL and DL
relay links.
5. The method of claim 1, wherein the information associated with
any preexisting access links with the UE comprises a total number
of access links that the UE can support and a number of access
links currently supported by the UE.
6. The method of claim 5, further comprising: broadcasting the
total number of access links that the UE can support and the number
of access links currently supported by the UE.
7. The method of claim 1, wherein the other UE UL interference
comprises an averaged received interference power value.
8. The method of claim 1, wherein information associated with any
preexisting access links with the candidate UE comprises a total
number of access links that the candidate UE can support and a
number of access links currently supported by the candidate UE.
9. The method of claim 1, wherein the information associated with
any preexisting access links with the candidate UE comprises a
value indicating whether the candidate UE can support any more
access links.
10. The method of claim 1, further comprising: transmitting a
message to prompt the candidate UE to perform an evaluation to
determine whether the candidate UE can support the relay link.
11. The method of claim 10, wherein the performing the link
establishment further comprises: receiving an indication from the
candidate UE that the candidate UE can support the relay link.
12. The method of claim 1, further comprising: receiving a message
from the candidate UE prompting the UE perform an evaluation to
determine whether the UE can support the relay link.
13. The method of claim 1, wherein a preexisting access link exists
between a third UE and a fourth UE within the threshold vicinity of
the UE or the candidate UE, and wherein the information associated
with the preexisting access link within the threshold vicinity of
the UE or the candidate UE further comprises at least one of: a
value indicating a number of additional access links that can
allowed within the threshold vicinity of the third UE and the
fourth UE; or a value indicating whether any more access links can
be supported within the threshold vicinity of the third UE and the
fourth UE.
14. The method of claim 1, wherein the UE is an edge UE and wherein
the candidate UE is a relay UE, wherein the edge UE receives
service from an eNodeB through the relay UE.
15. The method of claim 1, wherein the UE is a relay UE and wherein
the candidate UE is an edge UE, wherein the edge UE receives
service from an eNodeB through the relay UE.
16. An apparatus for communication, comprising: means for
determining that a user equipment (UE) is able to establish a relay
link with a candidate UE based on at least one of information
associated with any preexisting access links with the candidate UE,
information associated with any preexisting accessing links within
a threshold vicinity of the UE or the candidate UE, or any other UE
uplink (UL) interference; means for determining that the candidate
UE is able to support the relay link based on information
associated with preexisting access links for the candidate UE; and
means for performing a link establishment process for the relay
link with the candidate UE based on the determinations.
17. The apparatus of claim 16, further comprising: means for
receiving a list of one or more candidate UEs from an eNodeB.
18. The apparatus of claim 16, further comprising: means for
performing measurements to detect one or more candidate UEs.
19. The apparatus of claim 16, wherein the relay link comprise at
least one of an UL relay link, a downlink (DL) relay link, or UL
and DL relay links.
20. The apparatus of claim 16, wherein the information associated
with any preexisting access links with the UE comprises a total
number of access links that the UE can support and a number of
access links currently supported by the UE.
21. The apparatus of claim 20, further comprising: means for
broadcasting the total number of access links that the UE can
support and the number of access links currently supported by the
UE.
22. The apparatus of claim 16, wherein the other UE UL interference
comprises an averaged received interference power value.
23. The apparatus of claim 16, wherein information associated with
any preexisting access links with the candidate UE comprises a
total number of access links that the candidate UE can support and
a number of access links currently supported by the candidate
UE.
24. The apparatus of claim 16, wherein the information associated
with any preexisting access links with the candidate UE comprises a
value indicating whether the candidate UE can support any more
access links.
25. The apparatus of claim 16, further comprising: means for
transmitting a message to prompt the candidate UE to perform an
evaluation to determine whether the candidate UE can support the
relay link.
26. The apparatus of claim 25, further comprising: means for
receiving an indication from the candidate UE that the candidate UE
can support the relay link.
27. The apparatus of claim 16, further comprising: means for
receiving a message from the candidate UE prompting the UE perform
an evaluation to determine whether the UE can support the relay
link.
28. The apparatus of claim 16, wherein a preexisting access link
exists between a third UE and a fourth UE within the threshold
vicinity of the UE or the candidate UE, and wherein the information
associated with the preexisting access link within the threshold
vicinity of the UE or the candidate UE further comprises at least
one of: a value indicating a number of additional access links that
can allowed within the threshold vicinity of the third UE and the
fourth UE; or a value indicating whether any more access links can
be supported within the threshold vicinity of the third UE and the
fourth UE.
29. The apparatus of claim 16, wherein the UE is an edge UE and
wherein the candidate UE is a relay UE, wherein the edge UE
receives service from an eNodeB through the relay UE.
30. The apparatus of claim 16, wherein the UE is a relay UE and
wherein the candidate UE is an edge UE, wherein the edge UE
receives service from an eNodeB through the relay UE.
31. An apparatus for communication, comprising: a processing system
configured to: determine that a user equipment (UE) is able to
establish a relay link with a candidate UE based on at least one of
information associated with any preexisting access links with the
candidate UE, information associated with any preexisting accessing
links within a threshold vicinity of the UE or the candidate UE, or
any other UE uplink (UL) interference; determine that the candidate
UE is able to support the relay link based on information
associated with preexisting access links for the candidate UE; and
perform a link establishment process for the relay link with the
candidate UE based on the determinations.
32. The apparatus of claim 31, wherein the processing system is
further configured to: receive a list of one or more candidate UEs
from an eNodeB.
33. The apparatus of claim 31, wherein the processing system is
further configured to: perform measurements to detect one or more
candidate UEs.
34. The apparatus of claim 31, wherein the relay link comprise at
least one of an UL relay link, a downlink (DL) relay link, or UL
and DL relay links.
35. The apparatus of claim 31, wherein the information associated
with any preexisting access links with the UE comprises a total
number of access links that the UE can support and a number of
access links currently supported by the UE.
36. The apparatus of claim 35, wherein the processing system is
further configured to: broadcast the total number of access links
that the UE can support and the number of access links currently
supported by the UE.
37. The apparatus of claim 31, wherein the other UE UL interference
comprises an averaged received interference power value.
38. The apparatus of claim 31, wherein information associated with
any preexisting access links with the candidate UE comprises a
total number of access links that the candidate UE can support and
a number of access links currently supported by the candidate
UE.
39. The apparatus of claim 31, wherein the information associated
with any preexisting access links with the candidate UE comprises a
value indicating whether the candidate UE can support any more
access links.
40. The apparatus of claim 31, wherein the processing system is
further configured to: transmit a message to prompt the candidate
UE to perform an evaluation to determine whether the candidate UE
can support the relay link.
41. The apparatus of claim 40, wherein the processing system is
further configured to: receive an indication from the candidate UE
that the candidate UE can support the relay link.
42. The apparatus of claim 31, wherein the processing system is
further configured to: receive a message from the candidate UE
prompting the UE perform an evaluation to determine whether the UE
can support the relay link.
43. The apparatus of claim 31, wherein a preexisting access link
exists between a third UE and a fourth UE within the threshold
vicinity of the UE or the candidate UE, and wherein the information
associated with the preexisting access link within the threshold
vicinity of the UE or the candidate UE further comprises at least
one of: a value indicating a number of additional access links that
can allowed within the threshold vicinity of the third UE and the
fourth UE; or a value indicating whether any more access links can
be supported within the threshold vicinity of the third UE and the
fourth UE.
44. The apparatus of claim 31, wherein the UE is an edge UE and
wherein the candidate UE is a relay UE, wherein the edge UE
receives service from an eNodeB through the relay UE.
45. The apparatus of claim 31, wherein the UE is a relay UE and
wherein the candidate UE is an edge UE, wherein the edge UE
receives service from an eNodeB through the relay UE.
46. A computer program product, comprising: a computer-readable
medium comprising code for: determining that a user equipment (UE)
is able to establish a relay link with a candidate UE based on at
least one of information associated with any preexisting access
links with the candidate UE, information associated with any
preexisting accessing links within a threshold vicinity of the UE
or the candidate UE, or any other UE uplink (UL) interference;
determining that the candidate UE is able to support the relay link
based on information associated with preexisting access links for
the candidate UE; and performing a link establishment process for
the relay link with the candidate UE based on the
determinations.
47. The computer program product of claim 46, further comprising
code for: receiving a list of one or more candidate UEs from an
eNodeB.
48. The computer program product of claim 46, further comprising
code for: performing measurements to detect one or more candidate
UEs.
49. The computer program product of claim 46, wherein the relay
link comprise at least one of an UL relay link, a downlink (DL)
relay link, or UL and DL relay links.
50. The computer program product of claim 46, wherein the
information associated with any preexisting access links with the
UE comprises a total number of access links that the UE can support
and a number of access links currently supported by the UE.
51. The computer program product of claim 50, further comprising
code for: broadcasting the total number of access links that the UE
can support and the number of access links currently supported by
the UE.
52. The computer program product of claim 46, wherein the other UE
UL interference comprises an averaged received interference power
value.
53. The computer program product of claim 46, wherein information
associated with preexisting access links for the candidate UE
comprises a total number of access links that the candidate UE can
support and a number of access links currently supported by the
candidate UE.
54. The computer program product of claim 46, wherein the
information associated with any preexisting access links with the
candidate UE comprises a value indicating whether the candidate UE
can support any more access links.
55. The computer program product of claim 46, further comprising
code for: transmitting a message to prompt the candidate UE to
perform an evaluation to determine whether the candidate UE can
support the relay link.
56. The computer program product of claim 55, further comprising
code for: receiving an indication from the candidate UE that the
candidate UE can support the relay link.
57. The computer program product of claim 46, further comprising
code for: receiving a message from the candidate UE prompting the
UE perform an evaluation to determine whether the UE can support
the relay link.
58. The computer program product of claim 46, wherein a preexisting
access link exists between a third UE and a fourth UE within the
threshold vicinity of the UE or the candidate UE, and wherein the
information associated with the preexisting access link within the
threshold vicinity of the UE or the candidate UE further comprises
at least one of: a value indicating a number of additional access
links that can allowed within the threshold vicinity of the third
UE and the fourth UE; or a value indicating whether any more access
links can be supported within the threshold vicinity of the third
UE and the fourth UE.
59. The computer program product of claim 46, wherein the UE is an
edge UE and wherein the candidate UE is a relay UE, wherein the
edge UE receives service from an eNodeB through the relay UE.
60. The computer program product of claim 46, wherein the UE is a
relay UE and wherein the candidate UE is an edge UE, wherein the
edge UE receives service from an eNodeB through the relay UE.
Description
BACKGROUND
[0001] 1. Field
[0002] The present disclosure relates generally to communication
systems, and more particularly, to device-to device (D2D) relay
link selection and establishment in a long term evolution (LTE)
based access network.
[0003] 2. Background
[0004] Wireless communication systems are widely deployed to
provide various telecommunication services such as telephony,
video, data, messaging, and broadcasts. Typical wireless
communication systems may employ multiple-access technologies
capable of supporting communication with multiple users by sharing
available system resources (e.g., bandwidth, transmit power).
Examples of such multiple-access technologies include code division
multiple access (CDMA) systems, time division multiple access
(TDMA) systems, frequency division multiple access (FDMA) systems,
orthogonal frequency division multiple access (OFDMA) systems,
single-carrier frequency division multiple access (SC-FDMA)
systems, and time division synchronous code division multiple
access (TD-SCDMA) systems.
[0005] These multiple access technologies have been adopted in
various telecommunication standards to provide a common protocol
that enables different wireless devices to communicate on a
municipal, national, regional, and even global level. An example of
a telecommunication standard is LTE. LTE is a set of enhancements
to the Universal Mobile Telecommunications System (UMTS) mobile
standard promulgated by Third Generation Partnership Project
(3GPP). LTE is designed to better support mobile broadband Internet
access by improving spectral efficiency, lower costs, improve
services, make use of new spectrum, and better integrate with other
open standards using OFDMA on the downlink (DL), SC-FDMA on the
uplink (UL), and multiple-input multiple-output (MIMO) antenna
technology. LTE may support direct device-to-device (peer-to-peer)
communication.
[0006] As the demand for D2D communication increases, there exists
a need for methods/apparatuses for supporting various D2D
communication configurations within LTE.
SUMMARY
[0007] The following presents a simplified summary of one or more
aspects in order to provide a basic understanding of such aspects.
This summary is not an extensive overview of all contemplated
aspects, and is intended to neither identify key or critical
elements of all aspects nor delineate the scope of any or all
aspects. Its sole purpose is to present some concepts of one or
more aspects in a simplified form as a prelude to the more detailed
description that is presented later.
[0008] In accordance with one or more aspects and corresponding
disclosure thereof, various aspects are described in connection
with D2D relay link selection in a LTE based access network. In one
example, a communications device is equipped to determine that the
communications device (e.g., a user equipment (UE)) is able to
establish a relay link with a candidate UE based on at least one of
information associated with any preexisting access links with the
candidate UE, information associated with any preexisting accessing
links within a threshold vicinity of the UE or the candidate UE, or
any other UE UL interference, determine that the candidate UE is
able to support the relay link based on information associated with
preexisting access links for the candidate UE, and perform a link
establishment process for the relay link with the candidate UE
based on the determinations.
[0009] According to related aspects, a method for D2D relay link
selection in a LTE based access network is provided. The method can
include determining that a UE is able to establish a relay link
with a candidate UE based on at least one of information associated
with any preexisting access links with the candidate UE,
information associated with any preexisting access links within a
threshold vicinity of the UE or the candidate UE, or any other UE
UL interference. Further, the method can include determining that
the candidate UE is able to support the relay link based on
information associated with preexisting access links for the
candidate UE. Moreover, the method may include performing a link
establishment process for the relay link with the candidate UE
based on the determinations.
[0010] Another aspect relates to a communications apparatus enabled
to perform D2D relay link selection in a LTE based access network.
The communications apparatus can include means for determining that
a UE is able to establish a relay link with a candidate UE based on
at least one of information associated with any preexisting access
links with the candidate UE, information associated with any
preexisting access links within a threshold vicinity of the UE or
the candidate UE, or any other UE UL interference. Further, the
communications apparatus can include means for determining that the
candidate UE is able to support the relay link based on information
associated with preexisting access links for the candidate UE.
Moreover, the communications apparatus can include means for
performing a link establishment process for the relay link with the
candidate UE based on the determinations.
[0011] Another aspect relates to a communications apparatus. The
apparatus can include a processing system configured to determine
that a UE is able to establish a relay link with a candidate UE
based on at least one of information associated with any
preexisting access links with the candidate UE, information
associated with any preexisting access links within a threshold
vicinity of the UE or the candidate UE, or any other UE UL
interference. Further, the processing system may be configured to
determine that the candidate UE is able to support the relay link
based on information associated with preexisting access links for
the candidate UE. Moreover, the processing system may further be
configured to perform a link establishment process for the relay
link with the candidate UE based on the determinations.
[0012] Still another aspect relates to a computer program product,
which can have a computer-readable medium including code for
determining that a UE is able to establish a relay link with a
candidate UE based on at least one of information associated with
any preexisting access links with the candidate UE, information
associated with any preexisting access links within a threshold
vicinity of the UE or the candidate UE, or any other UE UL
interference. Further, the computer-readable medium may include
code for determining that the candidate UE is able to support the
relay link based on information associated with preexisting access
links for the candidate UE. Moreover, the computer-readable medium
can include code for performing a link establishment process for
the relay link with the candidate UE based on the
determinations.
[0013] To the accomplishment of the foregoing and related ends, the
one or more aspects comprise the features hereinafter fully
described and particularly pointed out in the claims. The following
description and the annexed drawings set forth in detail certain
illustrative features of the one or more aspects. These features
are indicative, however, of but a few of the various ways in which
the principles of various aspects may be employed, and this
description is intended to include all such aspects and their
equivalents.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] FIG. 1 is a diagram illustrating an example of a network
architecture.
[0015] FIG. 2 is a diagram illustrating an example of an access
network.
[0016] FIG. 3 is a diagram illustrating an example of a DL frame
structure in LTE.
[0017] FIG. 4 is a diagram illustrating an example of an UL frame
structure in LTE.
[0018] FIG. 5 is a diagram illustrating an example of an evolved
Node B and user equipment in an access network.
[0019] FIG. 6 is a diagram illustrating a device-to-device
communications network.
[0020] FIG. 7 is a diagram illustrating a device-to-device
communications network that is configured to support D2D relay
links, according to an aspect.
[0021] FIG. 8 is a flow chart of a method of wireless
communication.
[0022] FIG. 9 is a conceptual data flow diagram illustrating the
data flow between different modules/means/components in an
exemplary apparatus.
[0023] FIG. 10 is a diagram illustrating an example of a hardware
implementation for an apparatus employing a processing system.
DETAILED DESCRIPTION
[0024] The detailed description set forth below in connection with
the appended drawings is intended as a description of various
configurations and is not intended to represent the only
configurations in which the concepts described herein may be
practiced. The detailed description includes specific details for
the purpose of providing a thorough understanding of various
concepts. However, it will be apparent to those skilled in the art
that these concepts may be practiced without these specific
details. In some instances, well known structures and components
are shown in block diagram form in order to avoid obscuring such
concepts.
[0025] Several aspects of telecommunication systems will now be
presented with reference to various apparatus and methods. These
apparatus and methods will be described in the following detailed
description and illustrated in the accompanying drawings by various
blocks, modules, components, circuits, steps, processes,
algorithms, etc. (collectively referred to as "elements"). These
elements may be implemented using electronic hardware, computer
software, or any combination thereof Whether such elements are
implemented as hardware or software depends upon the particular
application and design constraints imposed on the overall
system.
[0026] By way of example, an element, or any portion of an element,
or any combination of elements may be implemented with a
"processing system" that includes one or more processors. Examples
of processors include microprocessors, microcontrollers, digital
signal processors (DSPs), field programmable gate arrays (FPGAs),
programmable logic devices (PLDs), state machines, gated logic,
discrete hardware circuits, and other suitable hardware configured
to perform the various functionality described throughout this
disclosure. One or more processors in the processing system may
execute software. Software shall be construed broadly to mean
instructions, instruction sets, code, code segments, program code,
programs, subprograms, software modules, applications, software
applications, software packages, routines, subroutines, objects,
executables, threads of execution, procedures, functions, etc.,
whether referred to as software, firmware, middleware, microcode,
hardware description language, or otherwise.
[0027] Accordingly, in one or more exemplary embodiments, the
functions described may be implemented in hardware, software,
firmware, or any combination thereof If implemented in software,
the functions may be stored on or encoded as one or more
instructions or code on a computer-readable medium.
Computer-readable media includes computer storage media. Storage
media may be any available media that can be accessed by a
computer. By way of example, and not limitation, such
computer-readable media can comprise RAM, ROM, EEPROM, CD-ROM or
other optical disk storage, magnetic disk storage or other magnetic
storage devices, or any other medium that can be used to carry or
store desired program code in the form of instructions or data
structures and that can be accessed by a computer. Disk and disc,
as used herein, includes compact disc (CD), laser disc, optical
disc, digital versatile disc (DVD), floppy disk and Blu-ray disc
where disks usually reproduce data magnetically, while discs
reproduce data optically with lasers. Combinations of the above
should also be included within the scope of computer-readable
media.
[0028] FIG. 1 is a diagram illustrating an LTE network architecture
100. The LTE network architecture 100 may be referred to as an
Evolved Packet System (EPS) 100. The EPS 100 may include one or
more user equipment (UE) 102, an Evolved UMTS Terrestrial Radio
Access Network (E-UTRAN) 104, an Evolved Packet Core (EPC) 110, a
Home Subscriber Server (HSS) 120, and an Operator's IP Services
122. The EPS can interconnect with other access networks, but for
simplicity those entities/interfaces are not shown. As shown, the
EPS provides packet-switched services, however, as those skilled in
the art will readily appreciate, the various concepts presented
throughout this disclosure may be extended to networks providing
circuit-switched services.
[0029] The E-UTRAN includes the evolved Node B (eNB) 106 and other
eNBs 108. The eNB 106 provides user and control planes protocol
terminations toward the UE 102. The eNB 106 may be connected to the
other eNBs 108 via a backhaul (e.g., an X2 interface). The eNB 106
may also be referred to as a base station, a base transceiver
station, a radio base station, a radio transceiver, a transceiver
function, a basic service set (BSS), an extended service set (ESS),
or some other suitable terminology. The eNB 106 provides an access
point to the EPC 110 for a UE 102. Examples of UEs 102 include a
cellular phone, a smart phone, a session initiation protocol (SIP)
phone, a laptop, a personal digital assistant (PDA), a satellite
radio, a global positioning system, a multimedia device, a video
device, a digital audio player (e.g., MP3 player), a camera, a game
console, or any other similar functioning device. The UE 102 may
also be referred to by those skilled in the art as a mobile
station, a subscriber station, a mobile unit, a subscriber unit, a
wireless unit, a remote unit, a mobile device, a wireless device, a
wireless communications device, a remote device, a mobile
subscriber station, an access terminal, a mobile terminal, a
wireless terminal, a remote terminal, a handset, a user agent, a
mobile client, a client, or some other suitable terminology.
[0030] The UEs 102 may form D2D connections 103. In an aspect, the
D2D connection 103 may be configured to allow the UEs 102 to
communicate with each other. In another aspect, a UE 102 may act as
a relay for another UE 102 using the D2D connection 103. The D2D
connection 103 may provide a DL relay connection, an UL relay
connection, and/or both DL and UL relay connections. In an
operational aspect, the LTE network architecture 100 may allow for
use of idle UEs 102 to act as relays for nearby active UEs 102. In
an aspect, the idle UE (e.g., relay UE) may act as a relay for
another UE (e.g., edge UE) through a D2D connection 103. For each
relay candidate the impact of preexisting access links and UL links
on this relay candidate may be determined, and the impact of
choosing this candidate on preexisting access links may be
determined Based on these determinations, a relay that improves
end-to-end rate without impacting any existing access links may be
selected.
[0031] The eNB 106 is connected by an Si interface to the EPC 110.
The EPC 110 includes a Mobility Management Entity (MME) 112, other
MMEs 114, a Serving Gateway 116, and a Packet Data Network (PDN)
Gateway 118. The MME 112 is the control node that processes the
signaling between the UE 102 and the EPC 110. Generally, the MME
112 provides bearer and connection management. All user IP packets
are transferred through the Serving Gateway 116, which itself is
connected to the PDN Gateway 118. The PDN Gateway 118 provides UE
IP address allocation as well as other functions. The PDN Gateway
118 is connected to the Operator's IP Services 122. The Operator's
IP Services 122 may include the Internet, the Intranet, an IP
Multimedia Subsystem (IMS), and a PS Streaming Service (PSS).
[0032] FIG. 2 is a diagram illustrating an example of an access
network 200 in an LTE network architecture. In this example, the
access network 200 is divided into a number of cellular regions
(cells) 202. One or more lower power class eNBs 208 may have
cellular regions 210 that overlap with one or more of the cells
202. The lower power class eNB 208 may be a femto cell (e.g., home
eNB (HeNB)), pico cell, micro cell, or remote radio head (RRH). The
macro eNBs 204 are each assigned to a respective cell 202 and are
configured to provide an access point to the EPC 110 for all the
UEs 206, 212 in the cells 202. Some of the UEs 212 may be in
device-to-device communication. There is no centralized controller
in this example of an access network 200, but a centralized
controller may be used in alternative configurations. The eNBs 204
are responsible for all radio related functions including radio
bearer control, admission control, mobility control, scheduling,
security, and connectivity to the serving gateway 116.
[0033] The modulation and multiple access scheme employed by the
access network 200 may vary depending on the particular
telecommunications standard being deployed. In LTE applications,
OFDM is used on the DL and SC-FDMA is used on the UL to support
both frequency division duplexing (FDD) and time division duplexing
(TDD). As those skilled in the art will readily appreciate from the
detailed description to follow, the various concepts presented
herein are well suited for LTE applications. However, these
concepts may be readily extended to other telecommunication
standards employing other modulation and multiple access
techniques. By way of example, these concepts may be extended to
Evolution-Data Optimized (EV-DO) or Ultra Mobile Broadband (UMB).
EV-DO and UMB are air interface standards promulgated by the 3rd
Generation Partnership Project 2 (3GPP2) as part of the CDMA2000
family of standards and employs CDMA to provide broadband Internet
access to mobile stations. These concepts may also be extended to
Universal Terrestrial Radio Access (UTRA) employing Wideband-CDMA
(W-CDMA) and other variants of CDMA, such as TD-SCDMA; Global
System for Mobile Communications (GSM) employing TDMA; and Evolved
UTRA (E-UTRA), IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE
802.20, and Flash-OFDM employing OFDMA. UTRA, E-UTRA, UMTS, LTE and
GSM are described in documents from the 3GPP organization. CDMA2000
and UMB are described in documents from the 3GPP2 organization. The
actual wireless communication standard and the multiple access
technology employed will depend on the specific application and the
overall design constraints imposed on the system.
[0034] FIG. 3 is a diagram 300 illustrating an example of a DL
frame structure in LTE. A frame (10 ms) may be divided into 10
equally sized sub-frames. Each sub-frame may include two
consecutive time slots. A resource grid may be used to represent
two time slots, each time slot including a resource block. The
resource grid is divided into multiple resource elements. In LTE, a
resource block contains 12 consecutive subcarriers in the frequency
domain and, for a normal cyclic prefix in each OFDM symbol, 7
consecutive OFDM symbols in the time domain, or 84 resource
elements. For an extended cyclic prefix, a resource block contains
6 consecutive OFDM symbols in the time domain and has 72 resource
elements. A physical DL control channel (PDCCH), a physical DL
shared channel (PDSCH), and other channels may be mapped to the
resource elements.
[0035] FIG. 4 is a diagram 400 illustrating an example of an UL
frame structure in LTE. The available resource blocks for the UL
may be partitioned into a data section and a control section. The
control section may be formed at the two edges of the system
bandwidth and may have a configurable size. The resource blocks in
the control section may be assigned to UEs for transmission of
control information. The data section may include all resource
blocks not included in the control section. The UL frame structure
results in the data section including contiguous subcarriers, which
may allow a single UE to be assigned all of the contiguous
subcarriers in the data section.
[0036] A UE may be assigned resource blocks 410a, 410b in the
control section to transmit control information to an eNB. The UE
may also be assigned resource blocks 420a, 420b in the data section
to transmit data to the eNB. The UE may transmit control
information in a physical UL control channel (PUCCH) on the
assigned resource blocks in the control section. The UE may
transmit only data or both data and control information in a
physical UL shared channel (PUSCH) on the assigned resource blocks
in the data section. A UL transmission may span both slots of a
subframe and may hop across frequency.
[0037] A set of resource blocks may be used to perform initial
system access and achieve UL synchronization in a physical random
access channel (PRACH) 430. The PRACH 430 carries a random sequence
and cannot carry any UL data/signaling. Each random access preamble
occupies a bandwidth corresponding to six consecutive resource
blocks. The starting frequency is specified by the network. That
is, the transmission of the random access preamble is restricted to
certain time and frequency resources. There is no frequency hopping
for the PRACH. The PRACH attempt is carried in a single subframe (1
ms) or in a sequence of few contiguous subframes and a UE can make
only a single PRACH attempt per frame (10 ms).
[0038] FIG. 5 is a block diagram of an eNB 510 in communication
with a UE 550 in an access network. In the DL, upper layer packets
from the core network are provided to a controller/processor 575.
The controller/processor 575 implements the functionality of the L2
layer. In the DL, the controller/processor 575 provides header
compression, ciphering, packet segmentation and reordering,
multiplexing between logical and transport channels, and radio
resource allocations to the UE 550 based on various priority
metrics. The controller/processor 575 is also responsible for HARQ
operations, retransmission of lost packets, and signaling to the UE
550.
[0039] The transmit (TX) processor 516 implements various signal
processing functions for the L1 layer (i.e., physical layer). The
signal processing functions includes coding and interleaving to
facilitate forward error correction (FEC) at the UE 550 and mapping
to signal constellations based on various modulation schemes (e.g.,
binary phase-shift keying (BPSK), quadrature phase-shift keying
(QPSK), M-phase-shift keying (M-PSK), M-quadrature amplitude
modulation (M-QAM)). The coded and modulated symbols are then split
into parallel streams. Each stream is then mapped to an OFDM
subcarrier, multiplexed with a reference signal (e.g., pilot) in
the time and/or frequency domain, and then combined together using
an Inverse Fast Fourier Transform (IFFT) to produce a physical
channel carrying a time domain OFDM symbol stream. The OFDM stream
is spatially precoded to produce multiple spatial streams. Channel
estimates from a channel estimator 574 may be used to determine the
coding and modulation scheme, as well as for spatial processing.
The channel estimate may be derived from a reference signal and/or
channel condition feedback transmitted by the UE 550. Each spatial
stream is then provided to a different antenna 520 via a separate
transmitter 518TX. Each transmitter 518TX modulates an RF carrier
with a respective spatial stream for transmission.
[0040] At the UE 550, each receiver 554RX receives a signal through
its respective antenna 552. In another aspect, UE 550 may
communicate with other UEs similarly to how UE 550 communicates
with eNB 510. Each receiver 554RX recovers information modulated
onto an RF carrier and provides the information to the receive (RX)
processor 556. The RX processor 556 implements various signal
processing functions of the L1 layer. The RX processor 556 performs
spatial processing on the information to recover any spatial
streams destined for the UE 550. If multiple spatial streams are
destined for the UE 550, they may be combined by the RX processor
556 into a single OFDM symbol stream. The RX processor 556 then
converts the OFDM symbol stream from the time-domain to the
frequency domain using a Fast Fourier Transform (FFT). The
frequency domain signal comprises a separate OFDM symbol stream for
each subcarrier of the OFDM signal. The symbols on each subcarrier,
and the reference signal, is recovered and demodulated by
determining the most likely signal constellation points transmitted
by the eNB 510. These soft decisions may be based on channel
estimates computed by the channel estimator 558. The soft decisions
are then decoded and deinterleaved to recover the data and control
signals that were originally transmitted by the eNB 510 on the
physical channel. The data and control signals are then provided to
the controller/processor 559.
[0041] The controller/processor 559 implements the L2 layer. The
controller/processor can be associated with a memory 560 that
stores program codes and data. The memory 560 may be referred to as
a computer-readable medium. In the UL, the controller/processor 559
provides demultiplexing between transport and logical channels,
packet reassembly, deciphering, header decompression, control
signal processing to recover upper layer packets from the core
network. The upper layer packets are then provided to a data sink
562, which represents all the protocol layers above the L2 layer.
Various control signals may also be provided to the data sink 562
for L3 processing. The controller/processor 559 is also responsible
for error detection using an acknowledgement (ACK) and/or negative
acknowledgement (NACK) protocol to support HARQ operations.
[0042] In the UL, a data source 567 is used to provide upper layer
packets to the controller/processor 559. The data source 567
represents all protocol layers above the L2 layer. Similar to the
functionality described in connection with the DL transmission by
the eNB 510, the controller/processor 559 implements the L2 layer
for the user plane and the control plane by providing header
compression, ciphering, packet segmentation and reordering, and
multiplexing between logical and transport channels based on radio
resource allocations by the eNB 510. The controller/processor 559
is also responsible for HARQ operations, retransmission of lost
packets, and signaling to the eNB 510.
[0043] Channel estimates derived by a channel estimator 558 from a
reference signal or feedback transmitted by the eNB 510 may be used
by the TX processor 568 to select the appropriate coding and
modulation schemes, and to facilitate spatial processing. The
spatial streams generated by the TX processor 568 are provided to
different antenna 552 via separate transmitters 554TX. Each
transmitter 554TX modulates an RF carrier with a respective spatial
stream for transmission.
[0044] The UL transmission is processed at the eNB 510 in a manner
similar to that described in connection with the receiver function
at the UE 550. Each receiver 518RX receives a signal through its
respective antenna 520. Each receiver 518RX recovers information
modulated onto an RF carrier and provides the information to a RX
processor 570. The RX processor 570 may implement the L1 layer.
[0045] The controller/processor 575 implements the L2 layer. The
controller/processor 575 can be associated with a memory 576 that
stores program codes and data. The memory 576 may be referred to as
a computer-readable medium. In the UL, the controller/processor 575
provides demultiplexing between transport and logical channels,
packet reassembly, deciphering, header decompression, control
signal processing to recover upper layer packets from the UE 550.
Upper layer packets from the controller/processor 575 may be
provided to the core network. The controller/processor 575 is also
responsible for error detection using an ACK and/or NACK protocol
to support HARQ operations.
[0046] FIG. 6 is a diagram of a device-to-device communications
system 600. The device-to-device communications system 600 includes
a plurality of wireless devices 604, 606, 608, 610. The
device-to-device communications system 600 may overlap with a
cellular communications system, such as for example, a wireless
wide area network (WWAN). Some of the wireless devices 604, 606,
608, 610 may communicate together in device-to-device communication
using the DL/UL WWAN spectrum, some may communicate with the base
station 602, and some may do both. For example, as shown in FIG. 6,
the wireless devices 608, 610 are in device-to-device communication
and the wireless devices 604, 606 are in device-to-device
communication. The wireless devices 604, 606 are also communicating
with the base station 602.
[0047] The wireless device may alternatively be referred to by
those skilled in the art as user equipment (UE), a mobile station,
a subscriber station, a mobile unit, a subscriber unit, a wireless
unit, a wireless node, a remote unit, a mobile device, a wireless
communication device, a remote device, a mobile subscriber station,
an access terminal, a mobile terminal, a wireless terminal, a
remote terminal, a handset, a user agent, a mobile client, a
client, or some other suitable terminology. The base station may
alternatively be referred to by those skilled in the art as an
access point, a base transceiver station, a radio base station, a
radio transceiver, a transceiver function, a basic service set
(BSS), an extended service set (ESS), a Node B, an evolved Node B,
or some other suitable terminology.
[0048] The exemplary methods and apparatuses discussed infra are
applicable to any of a variety of wireless device-to-device
communications systems, such as for example, a wireless
device-to-device communication system based on FlashLinQ, WiMedia,
Bluetooth, ZigBee, or Wi-Fi based on the IEEE 802.11 standard. To
simplify the discussion, the exemplary methods and apparatus are
discussed within the context of LTE. However, one of ordinary skill
in the art would understand that the exemplary methods and
apparatuses are applicable more generally to a variety of other
wireless device-to-device communication systems.
[0049] FIG. 7 is a diagram of a device-to-device communications
system 700 configured to support use of idle UEs (e.g., UE 704) as
relays, for the nearby active UEs (e.g., UE 706), for communication
with a eNB 702. Device-to-device communications system 700 may
include one or more eNBs 702 and one or more UEs (704, 706, 708,
710, 712, 714). Although any UE may act as a relay UE, for the sake
of clarity, FIG. 7 depicts an aspect in which an edge UE 706
determines whether a candidate UE 704 may be selected as a relay UE
for a D2D relay connection 722. Further, in another aspect, the
process of selecting and establishing the D2D relay connection 722,
described herein, may be performed by an idle relay candidate UE
(e.g., UE 704), an edge UE (e.g., UE 706), and/or both UEs (704,
706). The D2D relay connection 722 may be established where an
improved end-to-end rate is expected without impacting existing
access links. In an aspect, the D2D relay connection 722 may
provide UL relaying, DL relaying, and/or both UL and DL
relaying.
[0050] In an operational aspect, UE 706 may determine whether any
relay candidate UEs (e.g., 704, 708, 710) are present in system
700. In an aspect, the UE 706 may receive a message 720 from an eNB
702 including a list/array/matrix, etc. indicating the presence of
the candidate UEs (e.g., 704, 708, 710). In another aspect, the UE
706 may listen for broadcasts 728 from other UEs. In such an
aspect, the broadcast 728 may include information about any
preexisting access links 726 and how many links the UE may support
in total. In another aspect, the UE 706 may provide similar
broadcast information 728 to other UEs (e.g., 704, 708, 710).
Further, the UE 706 may determine and/or be provided with
information associated with UL interference 724 from connections
between UEs (e.g., 704, 708, 710) and eNB 702. Still further, the
UE 706 may determine whether there are any pre-existing links 730
within the vicinity of the UE 706. Such pre-existing links 730 may
be between UEs (710 and 712, 708 and 714) that are not being
considered as a relay candidate UE 704.
[0051] Initially, UE 706 may determine whether it can support the
D2D relay connection 722 if it were to be established. This
determination may be based on information associated with any
preexisting access links with the UE, any pre-existing links 730
within the vicinity (e.g., within a threshold range) of the UE, any
other UE UL interference 724, etc. When the UE 706 determines it
can handle the creation of the D2D relay connection 722, the UE 706
may determine whether the relay candidate UE 704 can support the
D2D relay connection 722 if it were to be established. This
determination may be based on information associated with
preexisting access links 726 supported by the relay candidate UE
704 and a total number of access links that the relay candidate UE
704 may support. as noted above, the UE 706 may be aware of the
number of preexisting access links 726 supported by the relay
candidate UE 704 and a total number of access links that the relay
candidate UE 704 may support from broadcast information 728
provided by the relay candidate UE 704. In an aspect, the broadcast
information 728 may further indicate whether pre-existing links 730
may tolerate another interfering access link in the vicinity. In
such an aspect, the indication may be provided as a value
indicating a number of additional access links that may be
tolerated within the vicinity of the link 730, a value indicating
whether any more access links may be tolerated within the vicinity
of the link 730, etc. Where the UE 706 can support the D2D relay
connection 722 and the relay candidate UE 704 can support the D2D
relay connection 722, the UEs 704, 706 may establish the D2D relay
connection 722.
[0052] FIG. 8 is a flow chart 800 of a method of wireless
communication. The method may be performed by a UE (e.g., UE 704,
UE 706). Further, the functionality described in the blocks
depicted in flow chart 800 may be performed by various modules
(804, 906, 908, 910, 912) associated in the example apparatus 902
depicted in FIG. 9.
[0053] In an optional aspect, at block 802, a UE may determine that
one or more candidate UEs are present. In an aspect, the UE may
receive a list/array/matrix, etc. from an eNodeB indicating the
presence of the candidate UEs. In another aspect, the UE may
monitor the system for a duration of time to detect broadcasts from
any candidate UEs. In an aspect, reception module 904 may receive a
message 922 from eNB 702 indicating the presence of the other UEs
704, 710. In an aspect, reception module 904 may monitor for
broadcasts 920, 924 from other UEs 704, 710.
[0054] In an optional aspect, at block 804, the UE may broadcast
information about any preexisting access links and how many links
the UE may support in total. In an aspect, each active access link
may compute its current interference and maximum tolerable
interference and broadcasts this information. In another aspect,
the information about any preexisting access links may include a
value (e.g., a yes/no bit) indicating whether the UE may support
any more access links. In an aspect, the transmission module 912
may broadcast the information 928.
[0055] At block 806a, the UE may determine whether it is able to
establish a candidate relay link with a candidate UE of the one or
more candidate UEs. In an aspect, UE relay link capability module
906 may use received information (e.g. 922, 924) to determine the
UE capability 928. In an aspect, the candidate relay link may be an
uplink (UL) relay link, a downlink (DL) relay link, or UL and DL
relay links. In an aspect, the UE may determine whether it is able
to establish the candidate relay link based on information
associated with any preexisting access links with the UE, any
preexisting access links within the vicinity (e.g., within a
threshold range) of the UE, any other UE UL interference, etc. For
example, a first UE may attempt to establish a link with a relay
candidate UE in an environment in which there is also a
pre-existing link between a third UE and a fourth UE in the
vicinity of and visible to the first UE or the relay candidate UE.
In such an environment, the first UE and/or the relay candidate UE
may take into account any pre-existing access links with the first
UE and/or the relay candidate UE, and any pre-existing access links
within the vicinity of the first UE and/or the relay candidate UE.
In such an aspect, the impact of preexisting access links on the
candidate relay link may be determined as the in-degree of the
interference graph of access links. Further, for estimating the
rate seen on access link, it may be assumed that the access links
will use 1/(N+1) of the resource, where N is the in-degree. In
another aspect, the impact of other UE UL interference on the
candidate relay link may be determined as the (averaged) received
interference power.
[0056] If at block 806a, the UE determines that it is unable to
establish the candidate relay link with the candidate UE, then at
block 808, the process may terminate. In an aspect, relay link
determination module 910 may determine to not establish the
candidate relay link 930.
[0057] Once the UE determines it can establish the candidate relay
link with the candidate UE, then at block 806b, the impact of
choosing the candidate relay link on a preexisting access link is
determined by whether or not the candidate relay link will increase
the in-degree of the preexisting access link beyond the maximum
number (e.g., the broadcast information from block 804). In an
aspect, candidate UE relay link capability module 908 may use
received information (920, 922) to determine the capabilities 926
of a relay candidate UE 704. This determination can happen at the
UE and/or the candidate relay UE. In an aspect, the UE may send a
message to the candidate relay UE prompting the candidate relay UE
to perform an evaluation to determine whether the candidate relay
UE can support the relay link, and to send a message back to the UE
indicating whether the candidate relay UE can support the relay
link. In another aspect, the UE may receive a similar message
prompting the UE to perform an evaluation to determine whether the
UE can support a relay link.
[0058] If at block 806b, the UE and/or the candidate UE determines
that a preexisting link's in-degree is increased beyond the maximum
number, the process may terminate at block 808. As noted above,
relay link determination module 910 may determine to not establish
the candidate relay link 930.
[0059] Otherwise, at block 810, the UE may establish the candidate
relay link with the candidate UE. In an aspect, relay link
determination module 910 may determine to select the candidate
relay link 930 and may establish the relay link 930 through
assistance from transmission module 912.
[0060] FIG. 9 is a conceptual data flow diagram 900 illustrating
the data flow between different modules/means/components in an
example apparatus 902. The apparatus may be a UE (e.g., UE 704, UE
706). As described with reference to FIG. 8, the apparatus 902
includes a reception module 904, UE relay link capability module
906, candidate UE relay link capability module 908, relay link
determination module 910, and transmission module 912.
[0061] The apparatus may include additional modules that perform
each of the steps of the algorithm in the aforementioned flow chart
of FIG. 8. As such, each block in the aforementioned flow chart of
FIG. 8 may be performed by a module and the apparatus may include
one or more of those modules. The modules may be one or more
hardware components specifically configured to carry out the stated
processes/algorithm, implemented by a processor configured to
perform the stated processes/algorithm, stored within a
computer-readable medium for implementation by a processor, or some
combination thereof.
[0062] FIG. 10 is a diagram 1000 illustrating an example of a
hardware implementation for an apparatus 902' employing a
processing system 1014. The processing system 1014 may be
implemented with a bus architecture, represented generally by the
bus 1024. The bus 1024 may include any number of interconnecting
buses and bridges depending on the specific application of the
processing system 1014 and the overall design constraints. The bus
1024 links together various circuits including one or more
processors and/or hardware modules, represented by the processor
1004, the modules 904, 906, 908, 910, 912, and the
computer-readable medium 1006. The bus 1024 may also link various
other circuits such as timing sources, peripherals, voltage
regulators, and power management circuits, which are well known in
the art, and therefore, will not be described any further.
[0063] The processing system 1014 may be coupled to a transceiver
1010. The transceiver 1010 is coupled to one or more antennas 1020.
The transceiver 1010 provides a means for communicating with
various other apparatus over a transmission medium. The processing
system 1014 includes a processor 1004 coupled to a
computer-readable medium 1006. The processor 1004 is responsible
for general processing, including the execution of software stored
on the computer-readable medium 1006. The software, when executed
by the processor 1004, causes the processing system 1014 to perform
the various functions described supra for any particular apparatus.
The computer-readable medium 1006 may also be used for storing data
that is manipulated by the processor 1004 when executing software.
The processing system further includes at least one of the modules
904, 906, 908, 910, and 912. The modules may be software modules
running in the processor 1004, resident/stored in the
computer-readable medium 1006, one or more hardware modules coupled
to the processor 1004, or some combination thereof The processing
system 1014 may be a component of the UE 550 and may include the
memory 560 and/or at least one of the TX processor 568, the RX
processor 556, and the controller/processor 559.
[0064] In one configuration, the apparatus 902/902' for wireless
communication includes means for determining that a UE is able to
establish a relay link with a candidate UE based on at least one of
information associated with any preexisting access links with the
UE, information associated with any preexisting accessing links
within a threshold vicinity of the UE or the candidate UE, or any
other UE uplink UL interference, means for determining that the
candidate UE is able to support the relay link based on information
associated with preexisting access links for the candidate UE, and
means for performing a link establishment process for the relay
link with the candidate UE based on the determinations. In an
aspect, the apparatus 902/902' may further include means for
receiving a list of one or more candidate UEs from an eNodeB. In an
aspect, the apparatus 902/902' may further include means for
performing measurements to detect one or more candidate UEs. In an
aspect, the apparatus 902/902' may further include means for
broadcasting a total number of access links that the UE can support
and a number of access links currently supported by the UE. In an
aspect, the apparatus 902/902' may further include means for
transmitting a message to prompt the candidate UE to perform an
evaluation to determine whether the candidate UE can support the
relay link. In such an aspect, the apparatus 902/902' may further
include means for receiving an indication from the candidate UE
that the candidate UE can support the relay link. In an aspect, the
apparatus 902/902' may further include means for receiving a
message from the candidate UE prompting the UE perform an
evaluation to determine whether the UE can support the relay
link.
[0065] The aforementioned means may be one or more of the
aforementioned modules of the apparatus 902 and/or the processing
system 1014 of the apparatus 902' configured to perform the
functions recited by the aforementioned means. As described supra,
the processing system 1014 may include the TX Processor 568, the RX
Processor 556, and the controller/processor 559. As such, in one
configuration, the aforementioned means may be the TX Processor
568, the RX Processor 556, and the controller/processor 559
configured to perform the functions recited by the aforementioned
means.
[0066] It is understood that the specific order or hierarchy of
steps in the processes disclosed is an illustration of exemplary
approaches. Based upon design preferences, it is understood that
the specific order or hierarchy of steps in the processes may be
rearranged. Further, some steps may be combined or omitted. The
accompanying method claims present elements of the various steps in
a sample order, and are not meant to be limited to the specific
order or hierarchy presented.
[0067] The previous description is provided to enable any person
skilled in the art to practice the various aspects described
herein. Various modifications to these aspects will be readily
apparent to those skilled in the art, and the generic principles
defined herein may be applied to other aspects. Thus, the claims
are not intended to be limited to the aspects shown herein, but is
to be accorded the full scope consistent with the language claims,
wherein reference to an element in the singular is not intended to
mean "one and only one" unless specifically so stated, but rather
"one or more." Unless specifically stated otherwise, the term
"some" refers to one or more. All structural and functional
equivalents to the elements of the various aspects described
throughout this disclosure that are known or later come to be known
to those of ordinary skill in the art are expressly incorporated
herein by reference and are intended to be encompassed by the
claims. Moreover, nothing disclosed herein is intended to be
dedicated to the public regardless of whether such disclosure is
explicitly recited in the claims. No claim element is to be
construed as a means plus function unless the element is expressly
recited using the phrase "means for."
* * * * *